Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Quantas vezes a data de vaga foi 14 de fevereiro de 2011?
 ###Tabelas: CREATE TABLE german_championship_finals_under_the_gauliga_system (german_championship_finals_under_the_gauliga_system_id AUTO_INCREMENT PRIMARY KEY, Year INT, Champion VARCHAR, Runner-Up VARCHAR, Result VARCHAR, Date VARCHAR, Venue VARCHAR, Attendance VARCHAR) CREATE TABLE european_tour_wins_12 (european_tour_wins_12_id AUTO_INCREMENT PRIMARY KEY, Date VARCHAR, Tournament VARCHAR, Winning score VARCHAR, Margin of victory VARCHAR, Runner(s)-up VARCHAR) CREATE TABLE members_clubs (members_clubs_id AUTO_INCREMENT PRIMARY KEY, Club VARCHAR, Coach VARCHAR, City VARCHAR, Stadium VARCHAR, 2007-2008 season VARCHAR) CREATE TABLE managerial_changes (managerial_changes_id AUTO_INCREMENT PRIMARY KEY, Team VARCHAR, Outgoing manager VARCHAR, Manner of departure VARCHAR, Date of vacancy VARCHAR, Replaced by VARCHAR, Date of appointment VARCHAR, Position in table VARCHAR) CREATE TABLE torneo_clausura (torneo_clausura_id AUTO_INCREMENT PRIMARY KEY, Position INT, Team VARCHAR, Played INT, Wins INT, Draws INT, Losses INT, Scored INT, Conceded INT, Points INT)  
SELECT COUNT Position in managerial_changes FROM managerial_changes WHERE Date of vacancy = 14 February 2011